A teenager summons the courage to fight off a serial killer and a perfect family is shattered by a mother’s brutal murder in a Saturday double feature of CBS News’ 48 HOURS to be broadcast August 10, 2013 on the CBS Television Network.

Tracy Smith and 48 HOURS report on the investigation into the shocking murder of Ruth Pyne in an updated rebroadcast of “The Perfect Family” to be broadcast at 10:00 PM, ET/PT. Pyne was stabbed and brutally beaten so badly that even veteran detectives were stunned by the brutality. Ruth Pyne was the matriarch of a seemingly all-American family living outside of Detroit. But after she was murdered, police investigating Ruth’s death revealed life wasn’t so perfect.

The investigation soon turned to the family, and investigators learned Ruth had some psychiatric issues that caused confrontations over her medications. Ruth and Bernie’s marriage also was troubled and Bernie had an affair. Ruth’s relationship with her son, Jeffrey, was also strained. Five months into the investigation, Jeffrey was charged with murder. However, his attorney said he didn’t do it and police have no direct evidence. Even Bernie doesn’t believe Jeffrey killed his mother. What will a jury think?

And at 9:00 PM, ET/PT, Shea McDonough takes viewers through the heart-stopping night when she awoke to a stranger holding a knife to her neck in an updated edition of 48 HOURS: “Live to Tell: Hunting Humans.” McDonough was just 15 that night in 2007, when the masked man broke into their Chelmsford, Mass., home and threatened to kill her if she made a noise. She screamed, and instantly and her father, Kevin, and her mother, Jeannie, were fighting with a knife-wielding man. While Kevin wrestled with the man, Shea called 911.

Police arriving on scene learned the attacker, Adam Leroy Lane, was heavily armed and in his truck was a DVD of a movie called “Hunting Humans” about a serial killer who murders people for the joy of it. The investigation would also lead police to unsolved murders in New Jersey and Pennsylvania. The McDonoughs recount their harrowing story in 48 HOURS: “Live to Tell: Hunting Humans.”

48 HOURS: “Live to Tell” is a unique franchise under the 48 Hours umbrella that delivers firsthand accounts of extraordinary people who refuse to give up when facing death. “Live to Tell: Hunting Humans” is produced by Chris Ritzen and Anthony Venditti. Jud Johnston, Gary Winter and Gregory McLaughlin are the producer editors. Kate Harrington is the update producer. Suzanne Allen is the senior coordinating producer. Judy Tygard created the concept and is the senior producer. Susan Zirinsky is the senior executive producer.